Condensed Consolidating Balance Sheet (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2012	Dec. 31, 2011
ASSETS
Cash and cash equivalents	$ 60,330	$ 62,897
Accounts receivable, net of allowance	232,863	252,764
Current deferred tax assets	5,360	8,022
Prepaid expenses and other current assets	20,048	27,059
Total current assets	318,601	350,742
Property and equipment, net	2,551,961	2,568,791
Restricted cash	5,023	5,022
Investment in direct financing lease	6,991	7,467
Goodwill	11,988	11,988
Other assets	35,813	30,732
Non-current deferred tax assets	5,998
Total assets	2,936,375	2,974,742
LIABILITIES AND STOCKHOLDERS' EQUITY
Accounts payable and accrued expenses	216,279	166,000
Income taxes payable	2,352	102
Current liabilities of discontinued operations	79	356
Total current liabilities	218,710	166,458
Long-term debt	1,016,948	1,111,545
Deferred tax liabilities		139,526
Other liabilities	38,815	35,593
Total liabilities	1,274,473	1,453,122
Total stockholders' equity	1,661,902	1,521,620	1,443,571	1,408,022
Total liabilities and stockholders' equity	2,936,375	2,974,742
Parent
ASSETS
Cash and cash equivalents	27,758
Accounts receivable, net of allowance	293,711	136,128
Current deferred tax assets	4	137
Prepaid expenses and other current assets	2,672	1,766
Total current assets	324,145	138,031
Property and equipment, net	2,452,362	2,462,917
Investment in direct financing lease	6,991	7,467
Other assets	198,110	191,502
Total assets	2,981,608	2,799,917
LIABILITIES AND STOCKHOLDERS' EQUITY
Accounts payable and accrued expenses	301,885	28,061
Total current liabilities	301,885	28,061
Long-term debt	1,016,948	1,111,545
Deferred tax liabilities	533	138,691
Other liabilities	340
Total liabilities	1,319,706	1,278,297
Total stockholders' equity	1,661,902	1,521,620
Total liabilities and stockholders' equity	2,981,608	2,799,917
Combined Subsidiary Guarantors
ASSETS
Cash and cash equivalents	32,572	62,897
Accounts receivable, net of allowance	276,506	255,192
Current deferred tax assets	5,356	7,885
Prepaid expenses and other current assets	26,836	35,175
Total current assets	341,270	361,149
Property and equipment, net	99,599	105,874
Restricted cash	5,023	5,022
Goodwill	11,988	11,988
Other assets	18,880	114,953
Non-current deferred tax assets	6,531
Total assets	483,291	598,986
LIABILITIES AND STOCKHOLDERS' EQUITY
Accounts payable and accrued expenses	261,174	286,342
Income taxes payable	2,352	102
Current liabilities of discontinued operations	79	356
Total current liabilities	263,605	286,800
Long-term debt	98,268	100,000
Deferred tax liabilities		835
Other liabilities	38,475	35,593
Total liabilities	400,348	423,228
Total stockholders' equity	82,943	175,758
Total liabilities and stockholders' equity	483,291	598,986
Consolidating Adjustments and Other
ASSETS
Accounts receivable, net of allowance	(337,354)	(138,556)
Prepaid expenses and other current assets	(9,460)	(9,882)
Total current assets	(346,814)	(148,438)
Other assets	(181,177)	(275,723)
Non-current deferred tax assets	(533)
Total assets	(528,524)	(424,161)
LIABILITIES AND STOCKHOLDERS' EQUITY
Accounts payable and accrued expenses	(346,780)	(148,403)
Total current liabilities	(346,780)	(148,403)
Long-term debt	(98,268)	(100,000)
Deferred tax liabilities	(533)
Total liabilities	(445,581)	(248,403)
Total stockholders' equity	(82,943)	(175,758)
Total liabilities and stockholders' equity	$ (528,524)	$ (424,161)